Filament support structure for incandescent lamps



A 21, 1951 L. G. LEIGHTON 3 FILAMENT SUPPORT STRUCTURE FOR INCANDESCENT LAMPS Filed S ept. 21, 1949 ITWQWLOF: Lerog G. Lejgfflton, 5 We K m His A k lrorneg.

Patented Aug. 21, 1951 FILAMENT SUPPORT STRUCTURE FOR INCANDESCENT LAMPS Leroy G. Leighton, Lyndhurst, Ohio, assignor to General Electric Company, a corporation of New York.

Application September 21, 1949, Serial No.'116,936

(Cl. 313-2'Z8) 4 Claims. 1

My invention relates to incandescent electric lamps and more particularly to lamps of the type having an elongated filament held under tension.

It is an object of my invention to provide an improved structure whereby the filament is maintained taut by suitable spring means having associated therewith a suitable brace structure which will minimize flexing of the spring means indirections transverse to the filament. The invention will be better understood from the following description taken in connection with the accompanying drawing which is a perspective view of a lamp embodying the invention.

The lamp shown in the drawing is of the same general type as that disclosed in Patent 2,467,? 10, I. H. Van Horn et al., which is assigned to the same assignee asv the present application. The lamp comprises an elongated tubular glass bulb I which may contain a suitable gas filling. A pair of lead-in conductors 2, 3 project into the lamp through a conventional stem 6 at one end thereof. The longer conductor 2 comprises an angular section 5 and a long straight section 6 extending longitudinally of the bulb to a point adjacent its remote end. The shorter conductor 3 comprises an angular section I and a short straight section 8 welded thereto. The filament 9 consists of a straight length of suitable wire, such as tungsten, secured at one end to the lead wire section 8 and at its other end to an auxiliary section IU of the lead wire. The said section if], and therefore the filament 9, is supported from the long lead wire section 6 by suitable spring means herein illustrated as consisting of a plurality (four) of helical springs H which are welded at their ends to the respective lead sections. The said spring members It, which preferably consist of helical coils of tungsten wire, maintain a tension on the filament 9. Although a single coil H may be sufiicient to maintain the necessary tension, in this case a plurality of coils is used in order to avoid overheating thereof by the large current flowing therethrough. The filament mount structure is additionally supported from the bulb by means of an angular length of wire l2 having one end welded to the lead wire section 6 and having its other end extending into the interior of a hollow glass nipple l3 fused to the tip of the bulb.

The lamp is also preferably provided with an elongated screen M to prevent blackening of the bulb. The screen I4 is preferably supported by a Wire frame 15 of shallow U-shape located substantially in the plane defined by the filament Q and conductor 6. The ends of the frame [5 are preferably welded to the conductor 6, and the screen [4 is preferably welded along its longitudinal center line to the base portion of the frame.

While the spring members ll effectively serve to maintain the filament 9 in a taut condition by their fiexure inthe plane including the conductor't. and filament 9, the said springs II are also flexible in directions transversely of that plane.v The said transverse fiexure is apt to give rise to difficulties, such as breakage of the joint between the filament and lead wire, and even entanglement of the filament with the screen 14, in case the lamp is subjected to shocks or vibration of sufficient magnitude. In accordance with the present invention I provide means to eliminate that difficulty, the means being herein illustrated as a U-shaped wire brace member ['6 which is fixedly supported in the bulb with its leg members arranged at opposite sides of the spring coils I l a substantial distance from the conductor 6 to effectively minimize transverse flexing of the coil springs II. Although the brace member I6 may be supported from the bulb or the filament mount structure in any suitable manner, it is herein illustrated as having its base welded to a portion of the frame member l5.

Although a preferred embodiment of my invention has been disclosed, it will be understood that the invention is not to be limited to the specific construction and arrangement of parts shown, but that they may be modified within the spirit and scope of my invention as defined in the appended claims. To this end, for example, the spring means I I may take other forms, and the brace means is may also be modified in structure and in its manner of support within the bulb.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electric incandescent lamp comprising an elongated bulb, a pair of rigid lead-in conductors projecting into one end of said bulb, one of said conductors extending a, substantial distance into the bulb beyond the other, an elongated filament extending longitudinally of said bulb and. having one end connected to the shorter one of said conductors, spring means connected to the opposite end of said filament and to the longer one of said conductors and extending transversely therebetween to support said filament and maintained taut, said spring means being flexible in directions transversely of said bulb as Well as longitudinally thereof, and brace means fixedly supported in said bulb and comprising members arranged at opposite sides of said spring means a substantial distance from said longer one of said conductors to minimize lateral movement of said filament due to transverse flexing of said spring means.

2. An electric incandescent lamp comprisin an elongated bulb, a pair of rigid lead-in conductors projecting into one'end of said bulb, one of said conductors extending a substantial distance into the bulb beyond the other, an elongated filament extending longitudinally of said bulb and having one end connected to the shorter one of said conductors, spring means connected to the opposite end of said filament and to the longer one of said conductors and extending transversely therebetween to support said filament and maintained taut, said spring means being flexible in directions transversely of said bulb as well as longitudinally thereof, and brace means fixedly supported in said bulb from said longer conductor and comprising members arranged at opposite sides of said spring means a substantial distance from said longer conductor to minimize lateral movement of said filament due to transverse flexing of said spring means.

3. An electric incandescent lamp comprising an elongated bulb, a pair of rigid lead-in conductors projectin into one end of said bulb, one of said conductors extending a substantial distance into the bulb beyond the other, an elongated filament extending longitudinally of said bulb and having one end connected to the shorter one of said conductors, spring means connected to the opposite end of said filament and to the l n r one of said conductors and extending transversely therebetween to support said filament 40 and maintain it taut, said spring means being 4 I flexible in directions transversely of said bulb as well as longitudinally thereof, and a U-shaped brace member fixedly supported in said bulb from said longer conductor and having its leg portions arranged at opposite sides of said spring means a substantial distance from said longer conductor to minimize lateral movement of said filament due to transverse flexing of said spring means.

4. An electric incandescent lamp comprising an elongated bulb, a pair of rigid lead-in conductors projecting into one end of said bulb, one of said conductors extending a substantial distance into the bulb beyond the other, an elongated filament extending longitudinally of said bulb substantially parallel to the longer one of said conductors and having one end connected to the shorter one of said conductors, a plurality of coil springs arranged in a row and each connected to the opposite end of said filament and to the said longer conductor and extending transversely therebetween in the plane including said filament and said longer conductor to support said filament and maintain it taut, said springs being flexible in directions transversely of said bulb as Well as longitudinally thereof, and brace means fixedly supported in said bulb and comprising members arranged at opposite sides of said springs substantially parallel to said filament and a substantial distance from said longer conductor to minimize lateral movement of said filament due to transverse flexing of said springs.

LEROY G. LEIGHTON.

REFERENCES CITED UNITED STATES PATENTS Name Date Van Horn Apr. 19, 1949 Number Certificate of Correction Patent No. 2,565,138 August 21,, 1951 LEROY G. LEIGHTON It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 2, line 55, and column 3, line 20, for maintained read maintain it;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 5th day of February, A. D1. 1952.

THOMAS F. MURPHY,

Assistant Gommz'ssioner of Patents. 

